The present invention relates to a thermoplastic resin composition capable of providing a molded product which is well-balanced in properties such as impact resistance and heat resistance and which has a uniformly and closely delustered surface.
Amorphous resins such as polystyrene resins (aromatic vinyl polymers), AS resins (vinyl cyanide-aromatic vinyl copolymers), polycarbonate resins, ABS resins (vinyl cyanide-conjugated diene type rubber-aromatic vinyl copolymers), AES resins (vinyl cyanide-ethylene/propylene type rubber-aromatic vinyl copolymers), polyphenylene ether resins and the like are used in various fields including motor vehicles, light electrical appliances, miscellaneous goods and so on becuase of their excellent moldability, impact resistance, rigidity and excellent surface gloss.
However, all of these properties are not always necessary depending on the intended uses. For example, in the fields of automobile interior parts, office or household electrical appliances and the like, there is a demand for materials such as polystyrene resins, polycarbonate resins or ABS resins which are improved in properties to reduce the surface gloss of the molded article for providing a uniformly and closely matted surface without impairing other mechanical and chemical properties. The purposes of using these materials are various and are, for instance, to prevent automobile interior parts from reflecting light in the night for safety or to provide electrical appliances with high grade appearance in view of the current trend toward high grade products.
It has been heretofore known to deluster the surface of molded products by adding a filler such as an oxide or carbonate of titanium, magnesium, calcium or the like to amorphous resins, e.g. polystyrene resins, polycarbonate resins, etc., or to crystalline resins, e.g. polypropylene, saturated polyester resins, etc. However, this method can not satisfactorily deluster the surface of molded products.
Also well known delustering methods comprise adding or grafting a rubber-like elastomer to the foregoing resins or using a composition containing a crosslinkable ethylene copolymer (Japanese Unexamined Patent Publication No.89346/1984). Yet, these methods remain unsatisfactory in delustering effect, and have the drawback of giving moldings having irregularly delustered surface due to uneven dispersion of said filler, elastomer or crosslinkable ethylene copolymer.